Predicting the invasive potential of a non-native mangrove reforested plant ( Laguncularia racemosa ) in China

Abstract(#br)Mangroves are critical inter-tidal ecosystems with high productivity and ecological significance. Afforestation was regarded as one of the key projects worldwide in recovering mangrove ecosystem function. Laguncularia racemosa, a non-native mangroves species in China has been used in mangrove afforestation, while its invasiveness is widely concerned. Understanding how it tolerates shade and salinity stresses is crucial as these factors can affect its invasive potential. However, the effects of soil salinity and light on mangroves (especially on non-native species) are ambiguous. We examined the combined effects of salinity and light on the growth and physiological responses of L. racemosa and predicted an extensive range of dispersal habitats for L. racemosa in a typical estuary using Kriging model. The field surveys showed that the seedling density and seedling height were positively correlated with light availability but negatively correlated with salinity. Our greenhouse experiment also demonstrated that moderate shading (60–80% PAR) and low salinity treatments (0–10 psu) enhanced the survival and growth of seedlings, whereas high salinity limited their assimilation rates ( A ), independent of the light levels. Under high salinity (30 psu) and low light level (20%), L. racemosa seedlings employed a water-saving strategy (248.96 ± 24.27 µmol·mmol −1 in instantaneous water use efficiency), which helped them to improve their adaptability to stressful environmental conditions and maintain their growth. Our findings indicate the combined effects of salinity and light on the growth strategies of L. racemosa as well as its environmental tolerance to high salinity which limits its growth and survival in coastal ecosystems. These results can provide a reference for the management of non-native mangrove species in China and worldwide

56.産褥貧血とその処置(第610回千葉医学会例会・昭和54年度産科婦人科分科会)

<p><b>Seasonal dynamics of (A, B) PEUE and (C, D) PNUE of alien <i>Sonneratia</i> and native mangrove species.</b> Fig 6 legend: Error bars represent ±1 SE.</p

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Surface complexation mechanism and modeling in Cr(III) biosorption by a microalgal isolate, Chlorella miniata

The mechanism involved in the removal of Cr(III) by a green microalgal isolate, Chlorella miniata, was examined based on a series of batch experiments and microscopic analyses, and a mathematical model was proposed. Results showed that Cr(III) biosorption increased with the increase of pH from 2.0 to 4.5, and no significant changes in biosorption outside this pH range. Langmuir isotherm indicated that the maximum Cr(III) sorption capacity of Chlorella miniata was 14.17, 28.72, and 41.12 mg g(-1) biomass at pH 3.0, 4.0, and 4.5, respectively. Results from desorption studies, SEM (scanning electron microscopy), TEM (transmission electron microscopy), and EDX (energy-dispersive X-ray spectroscope) analyses confirmed that surface complexation was the main process involved in Cr(III) biosorption. Potentiometric titration revealed that carboxyl (pK(al) = 4.10), phosphonate (pK(a2) = 6.36) and amine (pK(a3) = 8.47) functional groups on the surface of Chlorella miniata were the possible sites for Cr uptake, and their average amounts were 0.53, 0.39, and 0.36 mmol g-1 biomass, respectively. A surface complexation model further indicated that carboxyl group played the main role in Cr(III) complexation, with a binding constant of K-11 = 1.87 x 10(-4) and K-12 = 6.11 x 10(-4) for Cr3+ and Cr(OH)(2+), respectively. This model also suggested that the hydroxy species was more easily to complex with the cell surface of Chlorella miniata. (c) 2006 Elsevier Inc. All rights reserved

Diversity and Dynamics of Microbial Community Structure in Different Mangrove, Marine and Freshwater Sediments During Anaerobic Debromination of PBDEs

Little is known about the diversity and succession of indigenous microbial community during debromination of polybrominated diphenyl ethers (PBDEs). This study examined the diversity and dynamics of microbial community structure in eight saline (mangrove and marine) and freshwater sediment microcosms exhibiting different debrominating capabilities for hexa-BDE 153, a common congener in sediments, using terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses. The results showed that microbial community structure greatly differed between the saline and freshwater microcosms, likely leading to distinct variations in their debrominating capabilities and pathways. Higher relative abundances of Chloroflexi and Deltaproteobacteria succeed by Alphaproteobacteria and Betaproteobacteria were detected in the two mangrove microcosms with the fastest debrominating capabilities mainly via para pathway, respectively; the dominance of Alphaproteobacteria resulted in less accumulation of tetra-BDEs and more complete debromination of lower brominated congeners (from di- to tetra-BDEs). Meanwhile, the shifts in both microbial community structure and PBDE profiles were relatively small in the less efficient freshwater microcosms, with relatively more ortho and meta brominated products of BDE-153 resulted. Coincidently, one of the freshwater microcosms showed sudden increases of Chloroflexi and Deltaproteobacteria by the end of incubation, which synchronized with the increase in the removal rate of BDE-153. The significant relationship between microbial community structure and PBDEs was confirmed by redundancy analysis (18.7% of total variance explained, P = 0.002). However, the relative abundance of the well-known dechlorinator Dehalococcoides showed no clear correlation with the debrominating capability across different microcosms. These findings shed light in the significance of microbial community network in different saline environments on enhancement of PBDE intrinsic debromination

Anaerobic biodegradation of polycyclic aromatic hydrocarbons with amendment of iron(III) in mangrove sediment slurry

Mangrove sediment, influenced by tidal cycles, switches between low-oxygen and non-oxygen conditions, and iron is abundant in it. Polycyclic aromatic hydrocarbon (PAH) contamination often occurs in mangrove wetlands. In the present paper, the effects of iron [Fe(III)] amendment on the biodegradation of four mixed PAHs, namely fluorene (Fl). phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), in mangrove sediment slurries, with and without the inoculation of the enriched PAH-degrading bacterial consortia, under low-oxygen (2 +/- 0.3\% O-2) and non-oxygen (0\% O-2) conditions were investigated. Under both oxygen conditions and for all four PAHs, the highest PAHs biodegradation was observed in the groups with the inoculation of the enriched PAH-degrading consortia, while the groups without the inoculum and without Fe(III) amendment had the lowest biodegradation. However, the amendment of Fe(III) did not show any significant improvement on the biodegradation of all the four mixed PAHs. (c) 2010 Elsevier Ltd. All rights reserved

Genotypic responses of bacterial community structure to a mixture of wastewater-borne PAHs and PBDEs in constructed mangrove microcosms

Mangrove microcosms capable of removing polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) from wastewater were established under everyday tidal and non-tidal flooding regimes, along with two different mangrove species. Defining how bacterial communities change with pollutants or across treatments will contribute to understanding the microbial ecology of in situ bioremediation systems. A semi-nested PCR-DGGE (denaturing gradient gel electrophoresis) approach was employed, with known genus/species-specific primers targeting the 16S rRNA genes of Sphingomonas and Mycobacterium (related to PAH degradation) and Dehalococcoides (related to PBDE degradation). Results showed that the composition of Mycobacterium- and Dehalococcoides-like populations was critically determined by tidal regime during a medium-term (4-8 months) exposure, while that of Sphingomonas-like population, along with total bacterial community, was more dependent on sediment layer and became prominently affected by tidal regime till the end of 8-month treatment. The effect of plant species was relatively small. Canonical correspondence analysis (CCA) further revealed that Sphingomonas- and Mycobacterium-like populations were significantly associated with phenanthrene and benzo(a)pyrene, respectively, while Dehalococcoides-like population was the only group significantly related to the highest PBDE congener (BDE-209) in the mangrove microcosms. (C) 2015 Elsevier B.V. All rights reserved

Static and dynamic sorption of phenanthrene in mangrove sediment slurry

The static and dynamic sorption of phenanthrene (Phe) in three types of mangrove sediment slurries (sandy. silty and muddy) were described by three models, namely linear model, Freundlich adsorption isotherm model and Langmuir adsorption isotherm model. The Freundlich adsorption isotherm was the best model to describe the static sorption behavior of Phe in mangrove sediment Slurry with the regression coefficients ranging from 0.96 to 0.99. In static sorption, the sorption capacity and sorption intensity were reduced with the inoculation of Sphingomonas, a PAH-degrading bacterial isolate, suggesting that the inoculum even though inactive and/or dead would enhance bioavailability of Phe. On the other hand, the static sorption of Phe was significantly enhanced at high salinity (20 ppt) while no difference was found at low salinities ranging from 5 to 15 ppt. During the dynamic sorption process, i.e. with biodegradation by indigenous microorganisms and the inoculation of Sphingomonas, linear regression was the most suitable model to describe Phe sorption behavior. The partition coefficient a was the highest in silty sediment, followed by sandy sediment and the muddy sediment had the lowest value. These results indicated that the sorption behavior of Phe changed from non-linear to linear when biodegradation took place and the silty mangrove sediment slurry had the highest sorption affinity. (C) 2009 Elsevier B.V. All rights reserved